Bone marrow tissue in animals such as human or mouse plays an important role as a hematopoietic tissue. A technique for reassembling bone marrow tissue is very important for elucidation of the mechanisms of hematopoiesis and diseases associated therewith. However, since bone marrow is mostly composed of hemocytes, it has been difficult to reorganize once disintegrated.
As a culture technique pertaining to bone marrow, Dexter culture is known (Non-Patent Document No. 1: Dexter T M, Allen T D, Lajtha L G. Conditions controlling the proliferation of haemopoietic stem cells in vitro. J Cell Physiol. 1977 June; 91(3):335-44). This is a culture method which uses stroma cells as a feeder and enables hematopoietic stem cells to be maintained thereon or differentiated into various cells. This culture is performed in planar environments.
A technique is also known in which the above-described culture is performed with 3D scaffolds (Non-Patent Document No. 2: Nichols J E, Cortiella J, Lee J, Niles J A, Cuddihy M, Wang S, Bielitzki J, Cantu A, Mlcak R, Valdivia E, Yancy R, McClure M L, Kotov N A. In vitro analog of human bone marrow from 3D scaffolds with biomimetic inverted colloidal crystal geometry. Biomaterials. 2009 February; 30(6):1071-9; Non-Patent Document No. 3: Leisten I, Kramann R, Ventura Ferreira M S, Bovi M, Neuss S, Ziegler P, Wagner W, Knüchel R, Schneider R K. 3D co-culture of hematopoietic stem and progenitor cells and mesenchymal stem cells in collagen scaffolds as a model of the hematopoietic niche. Biomaterials. 2012 February; 33(6):1736-47).
Yu-usuke Torisawa et al. of the Wyss Institute, Harvard University have reported a research into a technique using a micro-fluid device for 3D reassembly of bone marrow (Non-Patent Document No. 4: Yu-suke Torisawa, Catherine S Spina, Tadanori Mammoto, Akiko Mammoto, James C Weaver, Tracy Tat, James J Collins, Donald E Ingber, Bone marrow-on-a-chip replicates hematopoietic niche physiology in vitro, Nature Methods, Vol 11, JUNE, 663-669 2014). They report that various hematopoietic events can be confirmed in vitro. A procedure for actual reassembling consists of filling the hollow part of cylindrical poly(dimethylsiloxane) (PDMS) with materials which reassemble bone and embedding the PDMS in the body of a mouse to thereby reassemble bone marrow together with bone. When the device is embedded in the mouse body, no living cells are used at all and bone marrow cells migrate by way of blood. Transplantation requires a period of 8 weeks. After 8 weeks, bone marrow tissue organized in the body is taken out, followed by perfusion in vitro using the micro-fluid device. Thus, hematopoietic events are investigated.